Study On The Fabrication And Properties Of Photonic Crystal Fiber

Since the first photonic crystal fiber (PCF) was fabricated in 1996, the technology of PCF is developing rapidly. The theory of PCF is continuously consummating. And the new designs of PCF are continually appearing. The vast improvements of the fabrication process have been obtained in recent years. The applications of PCF are widely studied. Now the PCF has been widely used in advanced front research of fiber optics and optoelectronics.In this dissertation, the transmission properties of PCF are investigated systematically and deeply. The fabrication process of PCF is investigated, while the key technique of PCF fabrication is achieved. The main achievements of this dissertation are as follows:(1) We theoretically analyzed the properties of PCF by the vectorial beam propagation method and vectorial finite element method. Both of these methods are having satisfactory numerical accuracy and computational efficiency. And there is a reasonable agreement between the calculated result and the experimental result.(2) We investigated the fabrication process of PCF and achieved the key technique of PCF fabrication. And we successfully used the stack-and-draw fabrication technique to fabricated a series of PCFs, such as endlessly single mode PCF, high birefringent PCF, highly nonlinear PCF, dispersion compensating PCF, dispersion flattened PCF.(3) The loss property is analysed specifically, then we proposed the improvement to reduce the level of loss. The loss of endlessly single mode PCF our fabricated can reach 0.4dB/km at 1550nm, which is the lowest level of PCF our fabricated.(4) We discussed the dispersion property with pitch, air-filling fraction. Then we designed a broadband dispersion compensating PCF based the index-guiding structure. It can compensate the dispersion of the single mode fiber in C+L band.(5) We proposed a novel PCF with defected-core. The small central defect of air hole can flexibly control the chromatic dispersion properties of this kind of photonic crystal fiber. Then we designed the broadband dispersion compensating PCF and the ultra-low and ultra-flattened dispersion PCF based this PCF index-guiding structure. And we fabricated the broadband dispersion compensating PCF with air-core according to the theoretical studies. The dispersion compensating photonic crystal fiber with air-core we fabricated has broadband large negative chromatic dispersion, and the chromatic dispersion coefficient varies from -440 to -480ps/(nm·km) in the measured wavelength range of 1500-1625nm. The calculated chromatic dispersion curve is well match to the measured result.(6) We simulated the ultra-low and ultra-flattened dispersion properties of photonic crystal fibers with defected-core, and applied to design PCF with ultra-low and ultra-flattened dispersion in the wavelength range of 1200～1600nm.(7) The dependence of nonlinear coefficient with pitch, air-filling fraction, and wavelength is analyzed systematically, that can be provided the theoretical basis to the practice. According to the theoretical analysis, we fabricated the highly nonlinear PCF. And the measured results of the highly nonlinear PCF are suitable to the calculation.